summaryrefslogtreecommitdiff
path: root/sound/pci/emu10k1/io.c
blob: 971458b45944b10ca7c65993f629caf231903954 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
/*
 *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
 *                   Creative Labs, Inc.
 *  Routines for control of EMU10K1 chips
 *
 *  BUGS:
 *    --
 *
 *  TODO:
 *    --
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <sound/driver.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/emu10k1.h>
#include <linux/delay.h>
#include "p17v.h"

unsigned int snd_emu10k1_ptr_read(struct snd_emu10k1 * emu, unsigned int reg, unsigned int chn)
{
	unsigned long flags;
	unsigned int regptr, val;
	unsigned int mask;

	mask = emu->audigy ? A_PTR_ADDRESS_MASK : PTR_ADDRESS_MASK;
	regptr = ((reg << 16) & mask) | (chn & PTR_CHANNELNUM_MASK);

	if (reg & 0xff000000) {
		unsigned char size, offset;
		
		size = (reg >> 24) & 0x3f;
		offset = (reg >> 16) & 0x1f;
		mask = ((1 << size) - 1) << offset;
		
		spin_lock_irqsave(&emu->emu_lock, flags);
		outl(regptr, emu->port + PTR);
		val = inl(emu->port + DATA);
		spin_unlock_irqrestore(&emu->emu_lock, flags);
		
		return (val & mask) >> offset;
	} else {
		spin_lock_irqsave(&emu->emu_lock, flags);
		outl(regptr, emu->port + PTR);
		val = inl(emu->port + DATA);
		spin_unlock_irqrestore(&emu->emu_lock, flags);
		return val;
	}
}

EXPORT_SYMBOL(snd_emu10k1_ptr_read);

void snd_emu10k1_ptr_write(struct snd_emu10k1 *emu, unsigned int reg, unsigned int chn, unsigned int data)
{
	unsigned int regptr;
	unsigned long flags;
	unsigned int mask;

	mask = emu->audigy ? A_PTR_ADDRESS_MASK : PTR_ADDRESS_MASK;
	regptr = ((reg << 16) & mask) | (chn & PTR_CHANNELNUM_MASK);

	if (reg & 0xff000000) {
		unsigned char size, offset;

		size = (reg >> 24) & 0x3f;
		offset = (reg >> 16) & 0x1f;
		mask = ((1 << size) - 1) << offset;
		data = (data << offset) & mask;

		spin_lock_irqsave(&emu->emu_lock, flags);
		outl(regptr, emu->port + PTR);
		data |= inl(emu->port + DATA) & ~mask;
		outl(data, emu->port + DATA);
		spin_unlock_irqrestore(&emu->emu_lock, flags);		
	} else {
		spin_lock_irqsave(&emu->emu_lock, flags);
		outl(regptr, emu->port + PTR);
		outl(data, emu->port + DATA);
		spin_unlock_irqrestore(&emu->emu_lock, flags);
	}
}

EXPORT_SYMBOL(snd_emu10k1_ptr_write);

unsigned int snd_emu10k1_ptr20_read(struct snd_emu10k1 * emu, 
					  unsigned int reg, 
					  unsigned int chn)
{
	unsigned long flags;
	unsigned int regptr, val;
  
	regptr = (reg << 16) | chn;

	spin_lock_irqsave(&emu->emu_lock, flags);
	outl(regptr, emu->port + 0x20 + PTR);
	val = inl(emu->port + 0x20 + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
	return val;
}

void snd_emu10k1_ptr20_write(struct snd_emu10k1 *emu, 
				   unsigned int reg, 
				   unsigned int chn, 
				   unsigned int data)
{
	unsigned int regptr;
	unsigned long flags;

	regptr = (reg << 16) | chn;

	spin_lock_irqsave(&emu->emu_lock, flags);
	outl(regptr, emu->port + 0x20 + PTR);
	outl(data, emu->port + 0x20 + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

int snd_emu10k1_spi_write(struct snd_emu10k1 * emu,
				   unsigned int data)
{
	unsigned int reset, set;
	unsigned int reg, tmp;
	int n, result;
	if (emu->card_capabilities->ca0108_chip)
		reg = 0x3c; /* PTR20, reg 0x3c */
	else {
		/* For other chip types the SPI register
		 * is currently unknown. */
		return 1;
	}
	if (data > 0xffff) /* Only 16bit values allowed */
		return 1;

	tmp = snd_emu10k1_ptr20_read(emu, reg, 0);
	reset = (tmp & ~0x3ffff) | 0x20000; /* Set xxx20000 */
	set = reset | 0x10000; /* Set xxx1xxxx */
	snd_emu10k1_ptr20_write(emu, reg, 0, reset | data);
	tmp = snd_emu10k1_ptr20_read(emu, reg, 0); /* write post */
	snd_emu10k1_ptr20_write(emu, reg, 0, set | data);
	result = 1;
	/* Wait for status bit to return to 0 */
	for (n = 0; n < 100; n++) {
		udelay(10);
		tmp = snd_emu10k1_ptr20_read(emu, reg, 0);
		if (!(tmp & 0x10000)) {
			result = 0;
			break;
		}
	}
	if (result) /* Timed out */
		return 1;
	snd_emu10k1_ptr20_write(emu, reg, 0, reset | data);
	tmp = snd_emu10k1_ptr20_read(emu, reg, 0); /* Write post */
	return 0;
}

/* The ADC does not support i2c read, so only write is implemented */
int snd_emu10k1_i2c_write(struct snd_emu10k1 *emu,
				u32 reg,
				u32 value)
{
	u32 tmp;
	int timeout = 0;
	int status;
	int retry;
	if ((reg > 0x7f) || (value > 0x1ff)) {
		snd_printk(KERN_ERR "i2c_write: invalid values.\n");
		return -EINVAL;
	}

	tmp = reg << 25 | value << 16;
	// snd_printk("I2C-write:reg=0x%x, value=0x%x\n", reg, value);
	/* Not sure what this I2C channel controls. */
	/* snd_emu10k1_ptr_write(emu, P17V_I2C_0, 0, tmp); */

	/* This controls the I2C connected to the WM8775 ADC Codec */
	snd_emu10k1_ptr20_write(emu, P17V_I2C_1, 0, tmp);
	tmp = snd_emu10k1_ptr20_read(emu, P17V_I2C_1, 0); /* write post */

	for (retry = 0; retry < 10; retry++) {
		/* Send the data to i2c */
		//tmp = snd_emu10k1_ptr_read(emu, P17V_I2C_ADDR, 0);
		//tmp = tmp & ~(I2C_A_ADC_READ|I2C_A_ADC_LAST|I2C_A_ADC_START|I2C_A_ADC_ADD_MASK);
		tmp = 0;
		tmp = tmp | (I2C_A_ADC_LAST|I2C_A_ADC_START|I2C_A_ADC_ADD);
		snd_emu10k1_ptr20_write(emu, P17V_I2C_ADDR, 0, tmp);

		/* Wait till the transaction ends */
		while (1) {
			udelay(10);
			status = snd_emu10k1_ptr20_read(emu, P17V_I2C_ADDR, 0);
                	// snd_printk("I2C:status=0x%x\n", status);
			timeout++;
			if ((status & I2C_A_ADC_START) == 0)
				break;

			if (timeout > 1000) {
                		snd_printk("emu10k1:I2C:timeout status=0x%x\n", status);
				break;
			}
		}
		//Read back and see if the transaction is successful
		if ((status & I2C_A_ADC_ABORT) == 0)
			break;
	}

	if (retry == 10) {
		snd_printk(KERN_ERR "Writing to ADC failed!\n");
		return -EINVAL;
	}
    
    	return 0;
}

int snd_emu1010_fpga_write(struct snd_emu10k1 * emu, u32 reg, u32 value)
{
	if (reg > 0x3f)
		return 1;
	reg += 0x40; /* 0x40 upwards are registers. */
	if (value < 0 || value > 0x3f) /* 0 to 0x3f are values */
		return 1;
	outl(reg, emu->port + A_IOCFG);
	udelay(10);
	outl(reg | 0x80, emu->port + A_IOCFG);  /* High bit clocks the value into the fpga. */
	udelay(10);
	outl(value, emu->port + A_IOCFG);
	udelay(10);
	outl(value | 0x80 , emu->port + A_IOCFG);  /* High bit clocks the value into the fpga. */

	return 0;
}

int snd_emu1010_fpga_read(struct snd_emu10k1 * emu, u32 reg, u32 *value)
{
	if (reg > 0x3f)
		return 1;
	reg += 0x40; /* 0x40 upwards are registers. */
	outl(reg, emu->port + A_IOCFG);
	udelay(10);
	outl(reg | 0x80, emu->port + A_IOCFG);  /* High bit clocks the value into the fpga. */
	udelay(10);
	*value = ((inl(emu->port + A_IOCFG) >> 8) & 0x7f);

	return 0;
}

/* Each Destination has one and only one Source,
 * but one Source can feed any number of Destinations simultaneously.
 */
int snd_emu1010_fpga_link_dst_src_write(struct snd_emu10k1 * emu, u32 dst, u32 src)
{
	snd_emu1010_fpga_write(emu, 0x00, ((dst >> 8) & 0x3f) );
	snd_emu1010_fpga_write(emu, 0x01, (dst & 0x3f) );
	snd_emu1010_fpga_write(emu, 0x02, ((src >> 8) & 0x3f) );
	snd_emu1010_fpga_write(emu, 0x03, (src & 0x3f) );

	return 0;
}

void snd_emu10k1_intr_enable(struct snd_emu10k1 *emu, unsigned int intrenb)
{
	unsigned long flags;
	unsigned int enable;

	spin_lock_irqsave(&emu->emu_lock, flags);
	enable = inl(emu->port + INTE) | intrenb;
	outl(enable, emu->port + INTE);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_intr_disable(struct snd_emu10k1 *emu, unsigned int intrenb)
{
	unsigned long flags;
	unsigned int enable;

	spin_lock_irqsave(&emu->emu_lock, flags);
	enable = inl(emu->port + INTE) & ~intrenb;
	outl(enable, emu->port + INTE);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_voice_intr_enable(struct snd_emu10k1 *emu, unsigned int voicenum)
{
	unsigned long flags;
	unsigned int val;

	spin_lock_irqsave(&emu->emu_lock, flags);
	/* voice interrupt */
	if (voicenum >= 32) {
		outl(CLIEH << 16, emu->port + PTR);
		val = inl(emu->port + DATA);
		val |= 1 << (voicenum - 32);
	} else {
		outl(CLIEL << 16, emu->port + PTR);
		val = inl(emu->port + DATA);
		val |= 1 << voicenum;
	}
	outl(val, emu->port + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_voice_intr_disable(struct snd_emu10k1 *emu, unsigned int voicenum)
{
	unsigned long flags;
	unsigned int val;

	spin_lock_irqsave(&emu->emu_lock, flags);
	/* voice interrupt */
	if (voicenum >= 32) {
		outl(CLIEH << 16, emu->port + PTR);
		val = inl(emu->port + DATA);
		val &= ~(1 << (voicenum - 32));
	} else {
		outl(CLIEL << 16, emu->port + PTR);
		val = inl(emu->port + DATA);
		val &= ~(1 << voicenum);
	}
	outl(val, emu->port + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_voice_intr_ack(struct snd_emu10k1 *emu, unsigned int voicenum)
{
	unsigned long flags;

	spin_lock_irqsave(&emu->emu_lock, flags);
	/* voice interrupt */
	if (voicenum >= 32) {
		outl(CLIPH << 16, emu->port + PTR);
		voicenum = 1 << (voicenum - 32);
	} else {
		outl(CLIPL << 16, emu->port + PTR);
		voicenum = 1 << voicenum;
	}
	outl(voicenum, emu->port + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_voice_half_loop_intr_enable(struct snd_emu10k1 *emu, unsigned int voicenum)
{
	unsigned long flags;
	unsigned int val;

	spin_lock_irqsave(&emu->emu_lock, flags);
	/* voice interrupt */
	if (voicenum >= 32) {
		outl(HLIEH << 16, emu->port + PTR);
		val = inl(emu->port + DATA);
		val |= 1 << (voicenum - 32);
	} else {
		outl(HLIEL << 16, emu->port + PTR);
		val = inl(emu->port + DATA);
		val |= 1 << voicenum;
	}
	outl(val, emu->port + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_voice_half_loop_intr_disable(struct snd_emu10k1 *emu, unsigned int voicenum)
{
	unsigned long flags;
	unsigned int val;

	spin_lock_irqsave(&emu->emu_lock, flags);
	/* voice interrupt */
	if (voicenum >= 32) {
		outl(HLIEH << 16, emu->port + PTR);
		val = inl(emu->port + DATA);
		val &= ~(1 << (voicenum - 32));
	} else {
		outl(HLIEL << 16, emu->port + PTR);
		val = inl(emu->port + DATA);
		val &= ~(1 << voicenum);
	}
	outl(val, emu->port + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_voice_half_loop_intr_ack(struct snd_emu10k1 *emu, unsigned int voicenum)
{
	unsigned long flags;

	spin_lock_irqsave(&emu->emu_lock, flags);
	/* voice interrupt */
	if (voicenum >= 32) {
		outl(HLIPH << 16, emu->port + PTR);
		voicenum = 1 << (voicenum - 32);
	} else {
		outl(HLIPL << 16, emu->port + PTR);
		voicenum = 1 << voicenum;
	}
	outl(voicenum, emu->port + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_voice_set_loop_stop(struct snd_emu10k1 *emu, unsigned int voicenum)
{
	unsigned long flags;
	unsigned int sol;

	spin_lock_irqsave(&emu->emu_lock, flags);
	/* voice interrupt */
	if (voicenum >= 32) {
		outl(SOLEH << 16, emu->port + PTR);
		sol = inl(emu->port + DATA);
		sol |= 1 << (voicenum - 32);
	} else {
		outl(SOLEL << 16, emu->port + PTR);
		sol = inl(emu->port + DATA);
		sol |= 1 << voicenum;
	}
	outl(sol, emu->port + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_voice_clear_loop_stop(struct snd_emu10k1 *emu, unsigned int voicenum)
{
	unsigned long flags;
	unsigned int sol;

	spin_lock_irqsave(&emu->emu_lock, flags);
	/* voice interrupt */
	if (voicenum >= 32) {
		outl(SOLEH << 16, emu->port + PTR);
		sol = inl(emu->port + DATA);
		sol &= ~(1 << (voicenum - 32));
	} else {
		outl(SOLEL << 16, emu->port + PTR);
		sol = inl(emu->port + DATA);
		sol &= ~(1 << voicenum);
	}
	outl(sol, emu->port + DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

void snd_emu10k1_wait(struct snd_emu10k1 *emu, unsigned int wait)
{
	volatile unsigned count;
	unsigned int newtime = 0, curtime;

	curtime = inl(emu->port + WC) >> 6;
	while (wait-- > 0) {
		count = 0;
		while (count++ < 16384) {
			newtime = inl(emu->port + WC) >> 6;
			if (newtime != curtime)
				break;
		}
		if (count >= 16384)
			break;
		curtime = newtime;
	}
}

unsigned short snd_emu10k1_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
{
	struct snd_emu10k1 *emu = ac97->private_data;
	unsigned long flags;
	unsigned short val;

	spin_lock_irqsave(&emu->emu_lock, flags);
	outb(reg, emu->port + AC97ADDRESS);
	val = inw(emu->port + AC97DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
	return val;
}

void snd_emu10k1_ac97_write(struct snd_ac97 *ac97, unsigned short reg, unsigned short data)
{
	struct snd_emu10k1 *emu = ac97->private_data;
	unsigned long flags;

	spin_lock_irqsave(&emu->emu_lock, flags);
	outb(reg, emu->port + AC97ADDRESS);
	outw(data, emu->port + AC97DATA);
	spin_unlock_irqrestore(&emu->emu_lock, flags);
}

/*
 *  convert rate to pitch
 */

unsigned int snd_emu10k1_rate_to_pitch(unsigned int rate)
{
	static u32 logMagTable[128] = {
		0x00000, 0x02dfc, 0x05b9e, 0x088e6, 0x0b5d6, 0x0e26f, 0x10eb3, 0x13aa2,
		0x1663f, 0x1918a, 0x1bc84, 0x1e72e, 0x2118b, 0x23b9a, 0x2655d, 0x28ed5,
		0x2b803, 0x2e0e8, 0x30985, 0x331db, 0x359eb, 0x381b6, 0x3a93d, 0x3d081,
		0x3f782, 0x41e42, 0x444c1, 0x46b01, 0x49101, 0x4b6c4, 0x4dc49, 0x50191,
		0x5269e, 0x54b6f, 0x57006, 0x59463, 0x5b888, 0x5dc74, 0x60029, 0x623a7,
		0x646ee, 0x66a00, 0x68cdd, 0x6af86, 0x6d1fa, 0x6f43c, 0x7164b, 0x73829,
		0x759d4, 0x77b4f, 0x79c9a, 0x7bdb5, 0x7dea1, 0x7ff5e, 0x81fed, 0x8404e,
		0x86082, 0x88089, 0x8a064, 0x8c014, 0x8df98, 0x8fef1, 0x91e20, 0x93d26,
		0x95c01, 0x97ab4, 0x9993e, 0x9b79f, 0x9d5d9, 0x9f3ec, 0xa11d8, 0xa2f9d,
		0xa4d3c, 0xa6ab5, 0xa8808, 0xaa537, 0xac241, 0xadf26, 0xafbe7, 0xb1885,
		0xb3500, 0xb5157, 0xb6d8c, 0xb899f, 0xba58f, 0xbc15e, 0xbdd0c, 0xbf899,
		0xc1404, 0xc2f50, 0xc4a7b, 0xc6587, 0xc8073, 0xc9b3f, 0xcb5ed, 0xcd07c,
		0xceaec, 0xd053f, 0xd1f73, 0xd398a, 0xd5384, 0xd6d60, 0xd8720, 0xda0c3,
		0xdba4a, 0xdd3b4, 0xded03, 0xe0636, 0xe1f4e, 0xe384a, 0xe512c, 0xe69f3,
		0xe829f, 0xe9b31, 0xeb3a9, 0xecc08, 0xee44c, 0xefc78, 0xf148a, 0xf2c83,
		0xf4463, 0xf5c2a, 0xf73da, 0xf8b71, 0xfa2f0, 0xfba57, 0xfd1a7, 0xfe8df
	};
	static char logSlopeTable[128] = {
		0x5c, 0x5c, 0x5b, 0x5a, 0x5a, 0x59, 0x58, 0x58,
		0x57, 0x56, 0x56, 0x55, 0x55, 0x54, 0x53, 0x53,
		0x52, 0x52, 0x51, 0x51, 0x50, 0x50, 0x4f, 0x4f,
		0x4e, 0x4d, 0x4d, 0x4d, 0x4c, 0x4c, 0x4b, 0x4b,
		0x4a, 0x4a, 0x49, 0x49, 0x48, 0x48, 0x47, 0x47,
		0x47, 0x46, 0x46, 0x45, 0x45, 0x45, 0x44, 0x44,
		0x43, 0x43, 0x43, 0x42, 0x42, 0x42, 0x41, 0x41,
		0x41, 0x40, 0x40, 0x40, 0x3f, 0x3f, 0x3f, 0x3e,
		0x3e, 0x3e, 0x3d, 0x3d, 0x3d, 0x3c, 0x3c, 0x3c,
		0x3b, 0x3b, 0x3b, 0x3b, 0x3a, 0x3a, 0x3a, 0x39,
		0x39, 0x39, 0x39, 0x38, 0x38, 0x38, 0x38, 0x37,
		0x37, 0x37, 0x37, 0x36, 0x36, 0x36, 0x36, 0x35,
		0x35, 0x35, 0x35, 0x34, 0x34, 0x34, 0x34, 0x34,
		0x33, 0x33, 0x33, 0x33, 0x32, 0x32, 0x32, 0x32,
		0x32, 0x31, 0x31, 0x31, 0x31, 0x31, 0x30, 0x30,
		0x30, 0x30, 0x30, 0x2f, 0x2f, 0x2f, 0x2f, 0x2f
	};
	int i;

	if (rate == 0)
		return 0;	/* Bail out if no leading "1" */
	rate *= 11185;		/* Scale 48000 to 0x20002380 */
	for (i = 31; i > 0; i--) {
		if (rate & 0x80000000) {	/* Detect leading "1" */
			return (((unsigned int) (i - 15) << 20) +
			       logMagTable[0x7f & (rate >> 24)] +
					(0x7f & (rate >> 17)) *
					logSlopeTable[0x7f & (rate >> 24)]);
		}
		rate <<= 1;
	}

	return 0;		/* Should never reach this point */
}